1. Field of the Invention
This invention relates partially to hydrostatic bearings of the kind, where an at least partially cylindrically formed body pivots or revolves on an at least partially hollow-cylindrical face of complementary configuration and size of a bearing body and where fluid under pressure is forced into the pivot or rotary bearing between the two bodies. In particularly the present invention is applied in the piston and piston shoe assembly of a radial piston machine, where the piston shoe pivots on a bed of the piston.
2. Description of the Prior Art
Typical radial piston machines, where a piston shoe pivots with a pivot portion in a bearing bed of a piston, are shown for example in my elder U.S. Pat. Nos. 3,223,046 and 3,277,834 while improvements of the pivot bearing between the piston and shoe are provided in my patent applications Ser. No. 802,231, now U.S. Pat. No. 4,206,690 or application Ser. No. 790,822, filed on Apr. 25, 1977, now abandoned but continued in application Ser. No. 121,356, which was filed on Feb. 14, 1980, now U.S. Pat. No. 4,452,127, issued on June 5, 1984. Similarly improved pivot bearings are also shown in my U.S. Pat. No. 4,479,420 which issed on Oct. 30, 1984.
The prior art of my patents and applications, which are here mentioned, already had a fluid pressure pocket in the pivot bar of the piston shoe. The fluid pressure pocket was however either a single concentrically located recess or plural recesses cut substantially in the direction of pivotion. For medial pressures the arrangments of the prior art have worked excellently. However, in presently used radial piston devices the pressures are increasing. Therefore, the pivot arrangements of the former art are not capable enough any more to handle the higher pressures. This is specially the case, because the sealing or bearing lands remain unlubricated, because they are side wards of the fluid pressure pockets. The high load at high pressure in the machine presses the fluid away from the bearing lands, whereby they are running dry, fail to lubricate and weld under extreme high pressures in the radial piston machine.
Other prior art is shown in many other patents, which are no Eickmann patents, and such other prior art errs by failing to recognize that the respective pivot bearings are overloaded bearings. The recesses applied in such other formed art fail to act as it was assumed that they would act.